1. Field of the Invention
The present invention relates to a transmission for an internal combustion engine of a saddle ride type vehicle for operating on wasteland (buggy car).
2. Description of Background Art
As described in Japanese Patent Publication No. Hei 8-1251, a conventional internal combustion engine of a saddle ride type vehicle is of the type wherein a crankshaft is disposed laterally and a transmission includes a main shaft, a counter shaft, a forward-running intermediate shaft, a backward-running intermediate shaft, and an output shaft, which are parallel to the crankshaft.
In the conventional structure, all the shafts are disposed laterally in parallel to each other, so that there is a defect wherein the lateral width of the crankcase is large and the front-side projection area of the crankcase is large. In addition, two intermediate shafts are provided for forward operating and backward operating and the number of rotary shafts is large, leading to an increase in the number of component parts, a rise in weight, and a rise in cost. Besides, since the number of shafts is large, there is a defect wherein the cross-sectional area orthogonal to the shafts is large.
The present invention aims at making it possible to make a compact transmission, to effectively utilize space, and to freely lay out component members, while disposing all shafts in the front-rear direction of a vehicle.
In addition, it is an object of the present invention is to provide a transmission system intended to improve the serviceability of a transmission by dividing a crankcase into parts in the longitudinal direction and disposing all of shafts in the longitudinal direction of a vehicle, to make the transmission compact by making effective use of space, and to optimize the arrangement of the members of the transmission system.
In order to solve the above-mentioned problems in the prior art, the present invention resides in a transmission for an internal combustion engine, including a crankshaft disposed in parallel to the operating direction of a vehicle body, and a forward-running/backward-running changeover mechanism, wherein the supply sources of a working oil and a lubricating oil for an automatic transmission are disposed concentratedly on the side of a front crankcase cover. The changeover mechanism is provided between a rear crankcase and a rear crankcase cover. A forward-running/backward-running changeover shift drum is disposed on the upper side of a plane containing the axis of a main shaft and the axis of a counter shaft of the transmission. One end portion of a shift spindle projects from the rear crankcase cover at a position on a lateral side of the shift drum.
According to the present invention constituted as above, the supply sources of the working oil and the lubricating oil for the automatic transmission are disposed concentratedly on the side of the front crankcase cover, so that it is easy to perform an inspection and/or maintenance of the hydraulic oil system or systems.
In addition, the forward-running/backward-running changeover mechanism is provided between the rear crankcase and the rear crankcase cover, and the changeover shift drum is disposed on the upper side of the plane containing the axis of the main shaft and the axis of the counter shaft of the transmission. Therefore, it is possible to effectively utilize space, to reduce the horizontal projection area of the transmission and to dispose a fuel tank and the like in a space on the lower side. Besides, since the shift spindle can be disposed at a high position, it is possible to easily protect a connection portion from a collision with stones or the like, without providing a rigid cover.
Moreover, according to the present invention, one end portion of the shift spindle projects from the rear crankcase cover at a position on a lateral side of the shift drum, so that an operation cable connected to a shift lever can be easily fitted.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.